I just got my first m43 camera (e-p3) and would like to get a zoom lens.

From what I've read, the Oly 40-150 seems to be a good choise (Quality/budget).

I was wondering if anyone could provide feedback on the difference between the older version and the new "R" version. The exterior has changed but I can't find what, if any, changes were made to the actual specs/performance...